code: def test_mul_stays_image(self):
      it = Tensor.randn(4).cast(dtypes.imagef((1, 1, 4))).realize()
      out = (it * 2).realize()
      assert isinstance(out.lazydata.base.realized.dtype, ImageDType)
  
file_path: tinygrad/test/test_image_dtype.py
imports: import unittest
  import numpy
  from tinygrad import Device, dtypes, Tensor, Variable
  from tinygrad.dtype import ImageDType
  from tinygrad.features.image import to_image_idx
label_desc: Use image node_id 4 for calling the TestImageDType obj's underlying member method code with example usage: obj.test_mul_stays_image() without return types